You can still talk about which modules you've used, and you can still describe the system you've built, without having to show actual code samples.

But if you're able to write some code of your own, or to contribute to CPAN in some small way, that helps as well. I heard that a fairly well-known CPAN contributor went in for a job interview, and because of his contributions to CPAN, they skipped right over the "Can you code" questions and went right to the "Here's the job we'd like you to do" discussion. That's an extreme example, but even if you've helped out here and there, that will go a long way to establishing your bona fides.